This page is how to recover ("unbrick") a broken BeagleBoard. It should help you if you messed your boot configuration and BeagleBoard doesn't boot any more the normal way ("bricked").
Normally, if you boot from MMC, you will get something like
in terminal program connected to UART (115200 8N1). This is output from OMAP3's bootrom while scanning the UART for boot source before trying to boot from MMC card. If you don't get this, but want to boot from MMC, most probably bootrom doesn't reach the MMC boot stage any more. If you played with NAND before getting this, most probably NAND contains some broken content.
What has happened?
Depending on user button OMAP3 on BeagleBoard uses different boot order. Normal order if user button isn't pressed at power up is boot from
NAND -> USB -> UART -> MMC
in this order. Depending on the boot medium (e.g. MMC) this might fail if something bad is in NAND flash which confuses OMAP3 bootrom thus stopping it to reach MMC boot stage.
This might happen if you e.g. mess your NAND, e.g. something went wrong using Steve's NAND flash procedure.
What to do now?
First, we have to press user button at power up to switch boot order to
USB -> UART -> MMC -> NAND
to have option to boot from other sources than broken NAND (which is first if user button is not pressed).
Then, there are three options to boot from:
Below, MMC and USB recovery will be done in detail.